EVE2 Startup for 7 inch Display

Hi Newhaven folks,

I'm following the FT81x Series Programmer Guide and the DS_FT81x datasheet to set my Newhaven display up and running.  I've been stuck for several days trying to get a hello world working.

My first test is to make a red circle on the screen.  It works very rarely and sometimes makes the circle the wrong size or at the bottom of the screen, sometimes it's only 1/2 or 1/4 circle.  Re-running startup randomly makes the screen kind of work, but the red dot location, size and presence is completely random.

• 10mhz single SPI.
• FTDI internal 12mhz crystal, not using external crystal.  (should I?)
• Particle Photon microcontroller.

Here's what I'm writing to the display, with comments.  I write to the display, then read back what I wrote in a follow-up transaction to see if it "took" properly.  First column is "milliseconds since bootup."

0000004092 [app.ft81x.display] INFO: wrote to register: 0x34, wrote: 0x00000320, read: 0x00000320.  good // Sets HSIZE=800
0000004092 [app.ft81x.display] INFO: wrote to register: 0x2c, wrote: 0x000003a0, read: 0x000003a0.  good // Sets HCYCLE=928
0000004093 [app.ft81x.display] INFO: wrote to register: 0x30, wrote: 0x00000058, read: 0x00000058.  good // Sets HOFFSET=88
0000004093 [app.ft81x.display] INFO: wrote to register: 0x38, wrote: 0x00000000, read: 0x00000000.  good // Sets HSYNC0=0
0000004094 [app.ft81x.display] INFO: wrote to register: 0x3c, wrote: 0x00000030, read: 0x00000030.  good // Sets HSYNC1=48
0000004095 [app.ft81x.display] INFO: wrote to register: 0x48, wrote: 0x000001e0, read: 0x000001e0.  good // Sets VSIZE=480
0000004095 [app.ft81x.display] INFO: wrote to register: 0x40, wrote: 0x0000020d, read: 0x0000020d.  good // Sets VCYCLE=525
0000004096 [app.ft81x.display] INFO: wrote to register: 0x44, wrote: 0x00000020, read: 0x00000020.  good // Sets VOFFSET=32
0000004096 [app.ft81x.display] INFO: wrote to register: 0x4c, wrote: 0x00000000, read: 0x00000000.  good // Sets VSYNC0=0
0000004097 [app.ft81x.display] INFO: wrote to register: 0x50, wrote: 0x00000003, read: 0x00000003.  good // Sets VSYNC1=3
0000004097 [app.ft81x.display] INFO: wrote to register: 0x6c, wrote: 0x00000001, read: 0x00000001.  good // Sets PCLK_POL=1 (falling edge, this is a curious setting in Newhaven's documentation)
0000004098 [app.ft81x.display] INFO: wrote to register: 0x68, wrote: 0x00000001, read: 0x00000001.  good // Sets CSPREAD=1
0000004098 [app.ft81x.display] INFO: wrote to register: 0x60, wrote: 0x00000001, read: 0x00000001.  good // Sets DITHER=1
0000004099 [app.ft81x.display] INFO: wrote to register: 0x64, wrote: 0x00000000, read: 0x00000000.  good // Sets SWIZZLE=0
0000004099 [app.ft81x.display] INFO: wrote to register: 0xd4, wrote: 0x00000080, read: 0x00000080.  good // Sets backlight PWM=128 (fully on)
0000004100 [app.ft81x.display] INFO: Settings are set.
0000004100 [app.ft81x.display] INFO: Waited 0ms for display list after register init.                           // This loops to wait for REG_DLSWAP's value to be 0
0000004101 [app.ft81x.display] INFO: Wrote display list: 0, command: 0x04000000, written: 0x04000000.  good // color_rgb(0,0,0) (display list number is (dl_offset)/4 for more convenient log reading)
0000004101 [app.ft81x.display] INFO: Wrote display list: 1, command: 0x26000007, written: 0x26000007.  good // clear(all)
0000004101 [app.ft81x.display] INFO: wrote to register: 0x54, wrote: 0x00000002, read: 0x00000002.  good // Writes 2 to REG_DLSWAP
0000004102 [app.ft81x.display] INFO: wrote to register: 0x70, wrote: 0x00000002, read: 0x00000002.  good // Sets PCLK=2 (Also a curious setting, FTDI programmer guide says this goes after the first display list)
0000004103 [app.ft81x.display] INFO: Waited 0ms for display list ready after initial clear display list. // This loops to wait for REG_DLSWAP's value to be 0
0000004103 [app.ft81x.display] INFO: Wrote display list: 0, command: 0x02000000, written: 0x02000000.  good // dl_ram+00 = color_rgb(0,0,0)
0000004104 [app.ft81x.display] INFO: Wrote display list: 1, command: 0x26000007, written: 0x26000007.  good // dl_ram+04 = clear(all)
0000004104 [app.ft81x.display] INFO: Wrote display list: 2, command: 0x04a01616, written: 0x04a01616.  good // dl_ram+08 = color_rgb(160,22,22)
0000004105 [app.ft81x.display] INFO: Wrote display list: 3, command: 0x0d000140, written: 0x0d000140.  good // dl_ram+12 = point_size(20+16)  (for a 40 pixel diameter circle)
0000004105 [app.ft81x.display] INFO: Wrote display list: 4, command: 0x1f000002, written: 0x1f000002.  good // dl_ram+16 = begin(point)
0000004106 [app.ft81x.display] INFO: Wrote display list: 5, command: 0x38085001, written: 0x38085001.  good // dl_ram+20 = vertex2ii(192,133,0,0)  (to try to drop the circle somewhere on the screen)
0000004106 [app.ft81x.display] INFO: Wrote display list: 6, command: 0x21000000, written: 0x21000000.  good // dl_ram+24 = end()
0000003908 [app.ft81x.display] INFO: wrote to register: 0x54, wrote: 0x00000002, read: 0x00000002.  good // Writes 2 to REG_DLSWAP

Am I interacting with the screen wrong?  Setting wrong settings?